Deep chilled air washer

TECHNICAL FIELD

p-0002The present application relates generally to gas turbine engines and more particularly relates to inlet air deep chilling and filtration systems for use with a gas turbine.

BACKGROUND OF THE INVENTION

p-0003Air chilling systems are often used with gas turbines to condition the inlet air temperature. Depending upon the ambient temperature, the use of the chilling systems with gas turbine engines may increase overall power output by a significant percentage. Specifically, the power output of the gas turbine is almost in reverse proportion to the inlet air temperature over a wide temperature range. For example, a known gas turbine may produce only about 154 megawatts of power at an ambient temperature of about 83 degrees Fahrenheit (about 28.3 degrees Celsius) but may produce about 171.2 megawatts of power at about 50 degrees Fahrenheit (about 10 degrees Celsius), an increase of more than about eleven percent. Likewise, the chilling systems may be run to temper the cold inlet air with waste heat in cooler ambient temperatures so as to provide efficient part load operation for the gas turbine.

p-0004One method of chilling the inlet air, as well as removing contaminants within the air stream, is through the use of a chilled water air washer system. Cooling the inlet air below about 40 degrees Fahrenheit (about 4.4 degrees Celsius) with a chilled water air washer system may be difficult in that it requires a reduction in the relative humidity and the dew point of the air stream. The temperature of the inlet air must be kept above the dew point so as to avoid condensation or freezing of the water contained in the air. Conventional chilling methods, however, may result in the air being very close to saturation, i.e., the relative humidity may be close to 100%. At this condition, the dew point is very close to the air temperature. As such, any further temperature loss may cause icing of components within or about the compressor inlet. These factors generally thus limit conventional inlet air cooling to about 38 to about 44 degrees Fahrenheit (about 3.3 to about 6.6 degrees Celsius).

p-0005There is thus a desire for improved gas turbine inlet air chilling systems. Such an inlet air chilling system should provide improved chilling of gas turbine inlet air while increasing overall system output and efficiency without the concern of freezing condensate.

SUMMARY OF THE INVENTION

p-0006The present application thus provides a deep chilled air washer for a gas turbine compressor. The deep chilled air washer may include one or more spray arrays for chilling an inlet air stream and one or more drift eliminators positioned downstream of the spray arrays. The drift eliminators may include a heating element therein so as to reheat the inlet air stream.

p-0007The present application further provides a method of chilling inlet air of a gas turbine. The method may include the steps of flowing the inlet air though through a spray of a fluid, lowering the temperature of the flow of the inlet air, capturing an amount of a condensate in the flow of the inlet air by the fluid, and heating the inlet air before entering the gas turbine.

p-0008The present application further provides for a deep chilled air washer for a gas turbine compressor. The deep chilled air washer may include one or more spray arrays for chilling an inlet air stream, a chiller condenser in communication with the spray arrays to chill the inlet air stream, one or more drift eliminators with a heating element therein so as to reheat the inlet air stream, and a chiller evaporator in communication with the heating element.

p-0009These and other features of the present application will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

p-0010<figref idrefs="DRAWINGS">FIG. 1</figref> is a schematic view of a gas turbine engine with an air chilling system.

p-0011<figref idrefs="DRAWINGS">FIG. 2</figref> is a schematic view of a gas turbine inlet air chilling system as is described herein.

DETAILED DESCRIPTION

p-0012Referring now to the drawings, in which like numerals refer to like elements throughout the several views, <figref idrefs="DRAWINGS">FIG. 1</figref> shows a schematic view of a gas turbine engine <b>10</b>. As is known, the gas turbine engine <b>10</b> may include a compressor <b>20</b> to compress an incoming flow of air. The compressor <b>20</b> delivers the compressed flow of air to a combustor <b>30</b>. The combustor <b>30</b> mixes the compressed flow of air with a flow of fuel and ignites the mixture. (Although only a single combustor <b>30</b> is shown, the gas turbine engine <b>10</b> may include any number of combustors <b>30</b>.) The hot combustion gases are delivered in turn to a turbine <b>40</b>. The turbine <b>40</b> drives the compressor <b>20</b> and an external load <b>50</b> such as an electrical generator and the like. The gas turbine engine <b>10</b> may use natural gas, various types of syngas, and other fuels. The gas turbine engine <b>10</b> may use other configurations and components herein.

p-0013In this example, the gas turbine engine <b>10</b> further includes a gas turbine inlet air cooling system <b>60</b>. The gas turbine inlet air cooling system <b>60</b> may be positioned about the compressor <b>20</b> and cools the incoming airflow to a desired temperature. The gas turbine inlet air cooling system <b>60</b> may use different cooling methods and may take many different configurations.

p-0014<figref idrefs="DRAWINGS">FIG. 2</figref> shows a gas turbine inlet air chilling system <b>60</b> in the form of a deep chilled air washer <b>100</b> as is described herein. As described above, the deep chilled air washer <b>100</b> may be positioned about the inlet of the compressor <b>20</b> of the gas turbine engine <b>10</b>. The deep chilled air washer <b>100</b> cools the inlet air stream and removes contaminants therein via a water wash.

p-0015The deep chilled air washer <b>100</b> may include a first stage spray array <b>110</b>. The first stage spray array <b>110</b> may include a number of spray nozzle pairs <b>120</b>. The spray nozzle pairs <b>120</b> may be of conventional design. Any number of spray nozzle pairs <b>120</b> may be used herein. As is shown, each spray nozzle pair <b>120</b> creates a spray pattern <b>125</b> in the form of an inverted double cone. Other types of spray patterns <b>125</b> may be used herein. In the aggregate, these spray patterns <b>125</b> create a water curtain effect for the inlet air to pass therethrough. Other types of water spray systems also may be used herein.

p-0016The deep chilled air washer <b>100</b> also may include a second stage spray array <b>130</b>. The second stage spray array <b>130</b> also may include a number of spray nozzle pairs <b>120</b> as are described above. Any number of spray nozzle pairs <b>120</b> also may be used herein. The spray nozzle pairs <b>120</b> may provide the inverted double cone spray pattern <b>125</b> or any desired spray pattern. Additional spray arrays <b>110</b>, <b>130</b> also may be used herein. The size, the spacing, and the positioning of the spray arrays <b>110</b>, <b>130</b> may vary.

p-0017A number of drift eliminators <b>140</b> may be positioned downstream of the spray arrays <b>110</b>, <b>130</b>. The drift eliminators <b>140</b> generally prevent water carryover into the compressor <b>20</b> and/or other types of turbine equipment. Any number of drift eliminators <b>140</b> may be used herein. As will be described in more detail below, in this example, the drift eliminator <b>140</b> may be in the form or an indirect contact air reheater or other type of heating element or heat exchanger. Other configurations may be used herein.

p-0018The deep chilled air washer <b>100</b> may include a fluid recirculation system <b>150</b> with a fluid <b>155</b> therein. In this example, the fluid <b>155</b> used herein may be an antifreeze solution of any concentration. Specifically, the solution may be based on propylene glycol or a similar type of fluid. Propylene glycol acts as a freezing point suppressant. Propylene glycol also is non-toxic and environmentally friendly. Other types of freezing point suppressants may be used herein.

p-0019The fluid <b>155</b> used in the second stage spray array <b>130</b> may be collected and stored in an intermediate solution well <b>160</b> or other type of container. The fluid <b>155</b> then may be pumped via a well pump <b>170</b> to the first stage spray array <b>110</b>. The well pump <b>170</b> may be of conventional design. Once used in the first stage spray array <b>110</b>, the fluid <b>155</b> again may be collected in an antifreeze solution well <b>180</b> or other type of container. Additional chilling also may be used herein.

p-0020The antifreeze solution of the fluid <b>155</b> used in the spray arrays <b>110</b>, <b>130</b> may be diluted from the condensate captured from the air. The fluid <b>155</b> thus may be pumped from the antifreeze solution well <b>180</b> via a concentrator pump <b>190</b> to a solution concentrator <b>200</b>. The solution concentrator <b>200</b> may separate the water from the antifreeze solution so as to maintain the fluid <b>155</b> at its desired concentrate level. The solution concentrator <b>200</b> may separate the water therein via a membrane or via thermal means to evaporate the water. Other types of concentrators may be used herein to maintain the concentration of the fluid <b>155</b>

p-0021The deep chilled air washer <b>100</b> also may include a cooling and heating system <b>210</b>. Inlet air systems typically use a chiller so as to chill the fluid flowing therein. The cooling and heating system <b>210</b> thus includes a chiller <b>220</b>. As is known, the chiller <b>200</b> includes a chiller evaporator <b>230</b> and a chiller condenser <b>240</b>. The chiller evaporator <b>230</b> chills the fluid <b>155</b> therein to the desired temperature before it is sent to the spray arrays <b>110</b>, <b>130</b>. Heat in the fluid stream generally is removed via the chiller condenser <b>240</b>. The chiller condenser <b>240</b> generally is in communication with a cooling tower (not shown) or other type of heat sink. In this example, however, the chiller condenser <b>140</b> may be in communication with the drift eliminators <b>140</b>. Specifically, the drift eliminators <b>140</b> may include a heated water loop <b>245</b> therein so as to provide indirect contact heating with the air stream passing therethrough. The hot water may be pumped via a drift eliminator pump <b>250</b>. The drift eliminators <b>140</b> may use any type of heating element, heat exchanger, or other type of device therein.

p-0022In use, inlet air may enter the deep chilled air washer <b>100</b> at about 50 degrees Fahrenheit (about 10 degrees Celsius). The air passes through the spray arrays <b>110</b>, <b>130</b> and may be chilled below freezing. For example, the inlet air stream may be chilled to about 18 degrees Fahrenheit (about −7.8 degrees Celsius). As the air passes through the spray arrays <b>110</b>, <b>130</b>, condensate in the air may be captured by the fluid <b>155</b>. As a result, the air may be close to the saturation point. To avoid icing about the compressor <b>20</b>, the air may be reheated to about 5 to about 8 degrees Fahrenheit (about −15 to about −13.3 degrees Celsius) above the dew point as it passes through the drift eliminator <b>140</b> and the heated water loop <b>245</b>.

p-0023The deep chilled air washer <b>100</b> thus reduces the water content of the air by condensation below the freezing point and then uses waste heat from the chiller <b>220</b> to reheat the air by a few degrees in the drift eliminator <b>140</b> to provide an anti-icing margin for the compressor <b>20</b>. Significantly, the use of the waste heat comes at virtually no cost to overall system efficiency. Condensate is then removed from the fluid <b>155</b> via the solution concentrator <b>200</b> and the cycle may be repeated.

p-0024The deep chilled air washer <b>100</b> thus may increase overall system output and efficiency in all weather conditions. Specifically, the inlet pressure drop may be reduced. Moreover, the cleaning of the inlet air should increase equipment lifetime and reliability.

p-0025It should be apparent that the foregoing relates only to certain embodiments of the present application and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.